Ignition timing control means for internal-combustion engines



Nov. 17, 1953 M. MALLORY 2,659,353

IGNITION TIMING CONTROL MEANS FOR INTERNAL-COMBUSTION ENGINES Filed July16, 1951 /3 j 4 c I ADVANCE R 7 4 9 b 2 a 3 7 M v, a a m U m N m In 0 E3 3 ENGINE R.P.M.

Fig. 2.

INVENTOR. Mar/on Mal/om ATTORNEYS.

Patented Nov. 17, 1953 OFFICE IGNITION TIMING CONTROL MEANS FORINTERNAL-COMBUSTION ENGINES Marion Mallory, Detroit, Mich. ApplicationJuly 16, 1951, Serial No. 237,037

11 Claims.

This invention relates to ignition timing control means for internalcombustion engines.

This invention is an improvement on the pressure ignition systems shownin my Patent 2,268,490 and in my copending application Serial No.207,369, filed January 23, 1951, and is concerned with an ignitiontiming control means which uses the manifold vacuum for both part andfull throttle spark control.

In the present day pressure ignition systems, such as shown in my patentand the above application, the servo-motor which advances and retard thespark is connected into the intake passageway through an orificepositioned just above or on the atmosphere side ofthe throttle valvewhen in idle position and this orifice passes on to the engine side ofthe throttle valve as soon as it is opened from idle position. With thistype of pressure ignition when the throttle valve is positioned slightlyabove the said on'fice, then the orifice is subjected to (1) the staticmanifold vacuum and (2) the velocity vacuum, that is, the vacuum inducedby the velocity flow of fluid by the throttle and orifice. Thecombination of the static manifold vacuum and the velocity vacuumproduces a combined vacuum which is higher than the manifold vacuum.This is undesirable because it produces too much spark advance anddetonation at part throttle. This undesirable situation for partthrottle spark advance can be solved by tightening or strengthening thespring which resists spark advance but this solution is not satisfactorybecause under such conditions when the throttle is wide open and thevacuum low, the velocity vacuum will not be able to overcome such astrong spring and not enough spark advance will be obtained for wideopen throttle operation. J

It is the object of this inventionto solve the above problem and remedythe above specified undesirable condition and this is efiected bybleeding down the combined velocity and static manifold vacuum at partthrottle operation to thereby eliminate the overage in vacuum due to thecombining of the velocity'and static manifold vacuums and thereby bringthe vacuum spark advance for part throttle operation back within itsproper range. 1

In the drawing: i

Fig. 1 is a sectional-view partly in elevation showing the mechanism ofmy ignition contro means for internal combustion engine.

' In Fig. 2' the curve A shows the Venturi' suction at wide openthrottle and the desired ignition or spark timing advance for thecorrespond- 3l is anchored at one end as at ing speed and curve B showsthe manifold suc tion at part throttle in my pressure ignition systemwhich is communicated to the servo-motor for advancing or retarding thespark and the desired spark timing advance for the corresponding speedwhich is obtained by my present ignition system.

Fig. 3 is a detail sectional view showing a modified form of myinvention.

The part illustrated in Fig. 1 of the drawings are as follows:carburetor I, venturi 2, air inlet 3 into the carburetor passageway,fuel mixture outlet 4 into the intake manifold, float bowl 5, fuelnozzle 6, throttle valve 1 of the butterfly type (throttle valve 1 ispreferably manually actuated by conventional means not shown), shaft 8journalled in carburetor housing I and supporting butterfly valve 1,orifice l positioned above on the atmosphere side of, and adjacent,throttle valve 1 when in idle position, pipe line H connecting orificeIn with suction device generally designated I 2.

The timing mechanism consists of the usual rotatable cam l4 whichrotates in the direction indicated by the arrow. I Cam 14 operates aconventional circuit breaker I5 (arm 34 pivoted on plate l6 at 35,rubbing block 36, contacts 31 and 38 mounted respectively on arm 34 andplate I6) mounted on plate |6-which can be rotated counterclockwise toadvance the spark and clockwise to retard the spark, as indicated.Suction device l2 is utilized for advancing and retarding the spark. I

Suction device l2 comprises a flexible diaphragm l1. Diaphragm I1 ismounted in housing I9. Diaphragm I l divides housing I 9 into chamberwhich communicates with atmosphere and into suction chamber 2| "whichis'in' communication with line H. Diaphragm I! is connected to plate Itby rod 22, one end of which :is pivotally connected the other end ofwhich is fixed to the diaphragm.

to plate l6-as at 23 and The ignition distributor housing is designated24. A tension coil spring 25 has one end anchored to post 26 fixedonplate l6 and the other end anchored to post 21 fixed on housing 24. Pin28, fixed to stationary housing 24, extends into arcuate slot 29 in'plate [6 and limits the rotation or oscillation of plate It to anynumber of degrees, preferably through an arc of about 40. Post 30 isfixed on plate [6' and leaf spring 32 to a bracket 33 fixed to, andwithin, housing 24. The free end of leaf spring 3| extends into the pathof post A second orifice 9 communicates with tube or pipe line H bybranch line I3. Orifice 9 is positioned in the intake passageway orcarburetor housing preferably adjacent to a plane (indicated by the lineC) perpendicular to the longitudinal axis of the carburetor or intakepassageway and passing through the uppermost tip 49 of the carburetorwhen in wide open position and, in any event, between this plane C andorifice III which is just above the throttle when in idle position. Inany event, orifice 9 should be positioned adjacent orifice so that itserves to bleed down the combined manifold and velocity vacuum obtainingat orifice H) as long as the throttle is in partly open position andparticularly when the throttle is open less than about half way betweenidle andwide open throttle positions.

If the spark advance required for wide open throttle is, say, forexample, 15, then this suction in-chamber 2| will act through diaphragml1 and rod 22 to move plate It and circuit breaker I counterclockwisethe required in an advance spark direction. Weak spring 25 willyieldably resist this counterclockwise rotation of plate It to advancethe spark. Since the Venturi suction at wide open throttle, e. g.,reaches about three inches of mercury, as indicated in Fig. 2, it isnecessary that spring 25 be a weak spring so that the spark will startto advance at around 500 R. P. M. engine speed when the vacuum is low.

In the above ignition timing system I accomplish ignition timing byopposing rotation of plate. It in a spark advance direction with astrong force (for example, the combined resistance or force of springs3|, 25) when the suction in chamber 2| is above maximum venturi orintake passageway suction (curve A),

and I use a weak force, that is, a weak spring 25 for opposing theventuri or intake passageway suction when it alone is acting uponsuction device I! to advance the spark. Spring ll, of course, does notact against post 39 and plate l6 unless the suctionin chamber 2| ishigher than the maximum Venturi or intake passageway suction, curve A.In other words, in my ignition timer I use a weak spring for the lowvacuums which exist in the suction device when the engine is operatingat wide open throttle thereby making the wide open throttle spark'curvestarting from low speed to high speed with the weak spring 25. The stiffspring is the limit of the spark advance any time-the throttle is wideopen regardless of the engine speed. When the vacuums in the suctiondevice are very hi h under part-throttle operation, then the stiff orstrong spring 8| opposes these vacuums in advancin the spark. The stiffspring 3| acts as a stop for the advance when the throttle is wide openand the engine running at high speeds. The low vacuum existing insuction device 2| when the engine is running at wide open throttle willnot advance the plate It against stifi spring 3| 4 throttle I is openedwide, then the spark advance falls back to curve A, Fig. 2.

In the form shown in Fig. 3, instead of two separate orifices 9 and IIIa single orifice 4| is used. This orifice in effect consists of wideningorifice 9 until it merges with orifice H) and the enlarged orifice 4|functions the same as orifices 9 and Hi. When the throttle is openedslightly above idle position, dotted line showing Fig. 3, then thestatic intake manifold vacuum and the velocity vacuum are imposed uponthe portion of enlarged orifice 4| below, or on the outlet side 4 of,throttle valve 9 but this combined vacuum is bled down from atmospherethrough the portion of orifice 4| above throttle valve 9 so that thespark is again advanced and retarded in accordance with curve B, Fig. 2.Here again orifice 4| should extend from a point slightly above thethrottle valve I when closed for idle to a point within the plane C,referred to above and shown in Fig. 1.

I claim:

1. In an internal combustion engine the combination of an ignition timeroperatable through a given range measured in degrees to advance andretard the ignition spark, a fuel mixture intake passageway, a manuallycontrolled throttle valve for said intake passageway, a suction deviceresponsive to intake passageway pressure f r v ncin and retarding saidignition timer, a conduit connecting said fuel mixture intake passagewaywith said suction device, said conduit communicating with said intakepassageway adjacent to, and on the atmosphere side of. said throttlevalve when the throttle valve is closed in idle position andcommunicating with said intake passageway simultaneously on both theinlet and outlet sides of said manually controlled throttle valve whenthe valve is partly open, the area of communication between said conduitand intake passageway being always located between the valve when closedfor idle and a plane passing through the upstream tip of the throttlevalve and perpendicular to the plane of the throttle valve when wideopen and being located entirely on the outlet side of the throttle valvewhen the throttle valve is open to a position greater than substantiallyhalf way between idle. and fully opened positions.

2. The combination defined in claim 1 wherein said throttle valve is abutterfly valve.

3. The combination defined in claim 2 wherein the communication betweenthe conduit and the intake passageway is in the form of a singleopening.

4. The combination defined in claim 2 wherein the communication betweensaid conduit and intake passageway is in the form of two openings, oneof which is positioned adjacent the throttle valve when closed for idleand the other of which is positioned above and between said firstorifice and a plane passing through the upstream tip of the throttlevalve when wide open.

5. In an internal combustion engine the combination of an ignition timeroperatable through a given range measured in degrees to advance andretard the ignition spark, a fuel mixture intake passageway, a throttlevalve for said intake passageway. a suction device responsive to intakepassageway pressure for advancing and retarding said ignition timer, aconduit connecting said fuel mixture intake passageway with said suctiondevice, said conduit communicating with said intake. passageway adJacentto, and onthe atmosphere side of, said throttle valve when the throttlevalve is closed in idle position and communicating with said intakepassageway on both the inlet and outlet sides of said throttle valvewhen the valve is partly open, the area, of communication between saidconduit and intake passageway being always located between the valvewhen closed for idle and a plane passing through the upstream tip of thethrottle valve and perpendicular to the plane of the throttle valve whenwide open, and resilient means yieldably opposing operation of the timerto advance the spark through a predetermined number of degrees andyieldably opposing further advance of the ignition timer with a greaterforce throughout the remaining range of adjustment of the timer tofurther advance the spark.

6. The combination claimed in claim 5 wherein said resilient meanscomprises two independent springs.

7. The combination claimed in claim 6 wherein the one spring opposesoperation of the timer to advance the spark throughout its entire rangeand the second spring is stronger than the first spring and opposesoperation of the timer to advance the spark only when the suction deviceis subjected to a suction greater than the maximum suction obtaining atsaid orifice at wide open throttle.

8. In an internal combustion engine the com bination of an ignitiontimer operatable through a given range measured in degrees to advanceand retard the ignition spark, a fuel mixture intake passageway, athrottle valve for said intake passageway, a suction device responsiveto intake passageway pressure for advancing and retarding said ignitiontimer, a conduit connecting said fuel mixture intake passageway withsaid suction device, said conduit communicating with said intakepassageway adjacent to, and on the atmosphere side of, said throttlevalve when the throttle valve is closed in idle position andcommunicating with said intake passageway on both the inlet and outletsides of said throttle valve when the valve is partly open, the area ofcommunication between said conduit and intake passageway being alwayslocated between the valve when closed for idle and a plane passingthrough the upstream tip of the throttle valve and perpendicular to theplane of the throttle valve when wide open, and a weak spring opposingsaid pressure actuated means when the pressure actuated means isresponding to wide open throttle suction and tending to advance thespark and a relatively stronger spring opposing said pressure actuatingmeans when the pressure actuated means is responding to part openthrottle suction and tending to advance the spark.

9. An ignition timer for an internal combustion engine having an intakepassageway and a manually controlled throttle valve positioned in saidintake passageway, a rotary cam, a support angularly adjustable aboutsaid cam, a circuit 7 breaker mounted on said support and arranged to beopened and closed by rotation of said cam, means connected to saidsupport for adjusting the same angularly about said cam to advance orretard the spark, said means comprising a suction device, a conduitconnecting said fuel mixture intake passageway with said suction device,said conduit communicating with said intake passageway adjacent to, andon the atmosphere side of, said manually controlled throttle valve whenthe throttle valve is closed in idle position and communicating withsaid intake passageway simultaneously on both the inlet and outlet sidesof said throttle valve when the valve is partly open, the area, ofcommunication between said conduit and intake passageway being alwayslocated between the valve when closed for idle and a plane passingthrough the upstream tip of the throttle valve and perpendicular to theplane of the throttle valve when wide open and being located entirely onthe outlet side of the throttle valve when the throttle valve is open toa position greater than substantially half way between idle and fullyopened positions.

10. An ignition timer for an internal combustion engine having an intakepassageway and a throttle valve positioned in said intake passageway, arotary cam, a support angularly adjustable about said cam, a circuitbreaker mounted on said support and arranged to be opened and closed byrotation of said cam, means connected to said support for adjusting thesame angularly about said cam to advance or retard the spark, said meanscomprising a suction device, a conduit connecting said fuel mixtureintake passageway with said suction device, said conduit communicatingwith said intake passageway adjacent to, and on the atmosphere side of,said throttle valve when the throttle valve is closed in idle positionand communicating with said intake passageway on both the inlet andoutlet sides of said throttle valve when the valve is partly open, thearea of communication between said conduit and intake passageway beingalways ioeated between the valve when closed for idle and a planepassing through the upstream tip of the throttle valve and perpendicularto the plane of the throttle valve when wide open, and resilient meansyieldably opposing angular movement of said support in a spark advancingdirection when the suction applied on the suction device through saidorifice and conduit is that obtaining at said orifice at substantiallywide open throttle operation and a relatively stronger resilient meansfor yieldably opposing such movement of the support when the suctionapplied on the suction device is that obtaining at said orifice at partopen throttle operation.

11. The combination set forth in claim 1 wherein the communicationbetween the conduit and the intake passageway is in the form of twoopenings, one of said openings being located closely adjacent andupstream from the valve when in closed idle position, the other openingbeing located closely adjacent and downstream of a plane passing throughthe upstream tip of the valve when in fully opened position andperpendicular to the plane of the valve when in fully opened position.

MARION MALLORY.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,388,628 Berdon Aug. 23, 1921 2,039,396 Darnell et al May 5,1936 2,066,640 Melcher et al. Jan. 5, 1937 2,134,354 Boyce Oct. 25, 1938

